How do I get data from a table?

in this code data is a two dimensional array of table data

let oTable = document.getElementById('datatable-id');
let data = [...oTable.rows].map(t => [...t.children].map(u => u.innerText))

This is how I accomplished reading a table in javascript. Basically I drilled down into the rows and then I was able to drill down into the individual cells for each row. This should give you an idea

//gets table
var oTable = document.getElementById('myTable');

//gets rows of table
var rowLength = oTable.rows.length;

//loops through rows    
for (i = 0; i < rowLength; i++){

   //gets cells of current row
   var oCells = oTable.rows.item(i).cells;

   //gets amount of cells of current row
   var cellLength = oCells.length;

   //loops through each cell in current row
   for(var j = 0; j < cellLength; j++){
      /* get your cell info here */
      /* var cellVal = oCells.item(j).innerHTML; */
   }
}

UPDATED - TESTED SCRIPT

<table id="myTable">
    <tr>
        <td>A1</td>
        <td>A2</td>
        <td>A3</td>
    </tr>
    <tr>
        <td>B1</td>
        <td>B2</td>
        <td>B3</td>
    </tr>
</table>
<script>
    //gets table
    var oTable = document.getElementById('myTable');

    //gets rows of table
    var rowLength = oTable.rows.length;

    //loops through rows    
    for (i = 0; i < rowLength; i++){

      //gets cells of current row  
       var oCells = oTable.rows.item(i).cells;

       //gets amount of cells of current row
       var cellLength = oCells.length;

       //loops through each cell in current row
       for(var j = 0; j < cellLength; j++){

              // get your cell info here

              var cellVal = oCells.item(j).innerHTML;
              alert(cellVal);
           }
    }
</script>